Training the Adaptive Filter

Thunderbird's adaptive filter requires training. When you first installed Thunderbird, there was no junk filter list. This list is always created, from scratch, based on your training.

Thunderbird stores the spam filter word list in a file named TRaining.dat. This is a binary file, with a file header and a series of variable-length records. Each record consists of a 4-byte hit count, a 4-byte integer specifying how long the token (a word or string) is, and then the token's contents. A token is usually a single word, although there are cases where it might be a compound word or other information.

Tip

The junk hit list, training.dat, is generated automatically as you use Thunderbird. To work correctly, you must not only mark emails as junk, but also mark non-junk emails as non-junk. If you feel that the Thunderbird junk mail filter is miscategorizing non-junk emails as junk, consider resetting the training data. When marking emails as junk, I recommend that you right-click the message and select Mark As Junk from the context menu. A right-click does not display the message or allow malicious content to be activated.